No, don’t worry, “How I Met Your Mother” is still one of the funniest sitcoms on network television. It’s just that it isn’t the secret love that it once was. After spending the previous reviews of “HIMYM” DVD sets with the primary thrust of “this is the best comedy you’re not watching,” that tactic must now officially be retired, thanks to the show picking up an unexpected but highly notable guest star: Britney Spears.

When it was announced that the former Mrs. Federline would be appearing on “HIMYM,” fans were predominantly pleased; most didn’t really care about it on a personal level, but since the curiosity factor alone was going to be bringing a lot of viewers into the show, it was hard to complain. But when she turned up a second time, a few accusations about stunt casting began to fly. Those charges are a bit hard to get behind, however, since Britney offered fine comedic turns on both occasions, with her character managing to get the shaft from both Ted and Barney. Indeed, the shafting from the latter was so pronounced that her character served as a plot device within a third episode. (It aired between her two appearances, but you won’t know which one it is until you’ve actually watched the second appearance. How’s that for confusing?)

Within Season Three of “HIMYM,” we finally begin to make some headway on the mystery of the mother of Ted’s kids, though longtime viewers will not be surprised to find that it’s slow going, and by season’s end, we still have no formal confirmation that we’ve met her. Ted does manage to recover well from his break-up with Robin; the pair suffer one notable backslide during the course of these 20 episodes (they have sex on Thanksgiving eve), but each manage to find their own romances. Granted, Robin’s tend to be more brief, but they’re at least entertaining and educational, with Gael (Enrique Iglesias) reminding her that her vacation self and her real-world self are utterly incompatible, and George confirming once and for all that she should never date guys who have kids. Ted, meanwhile, suffers through a girl whose eyes are just as crazy as she is (Abigail Spencer), a woman whose inability to shut up goes unnoticed by Ted until his friends shatter his ignorance (Lindsay Price, “Lipstick Jungle”), and a tattooed love girl (Mandy Moore) who leaves him with a tramp stamp. It’s hard to complain too much about the tattoo, however, since Ted’s need to have it removed leads him to Stella (Sarah Chalke, “Scrubs”), a doctor with whom he hits it off so well that, by season’s end, he’s popped the question.

Marshall and Lily enter wedded bliss with relative success, though their greatest battles throughout the season involve Marshall’s inability to get comfortable with his career choice (he passes the bar, but his ethics get in the way when it comes to choosing a firm) and Lily’s tremendously huge credit card debt, which she successfully keeps hidden from Marshall until the time comes for them to buy their own place. Barney, of course, remains quite steadfastly Barney; until the end of the season, that is, when he sleeps with Robin, finds it hard to keep it from Ted, and when the truth is revealed, their friendship is irreparably damaged. (Well, for a few episodes, anyway.) This leads Barney onto a very funny search for a new wingman, but more importantly, it leads him to realize that he just might have feelings for Robin.

In Season Three, “HIMYM” continues to fire on all comedic thrusters as well as to reward longtime viewers with regular callbacks to previous episodes. Robin’s Canadian pop star alter ego, Robin Sparkles, makes another appearance as Robin finds herself falling for an old beau despite everyone else being utterly appalled by him. There’s a great Final-Four-themed episode where Barney is forced to revisit several of his past conquests. Probably the most impressive callback, however, involves a reference to Ted’s “Pineapple Incident” during the first season, which not only allows for a return guest appearance by Danica McKellar (Winnie Cooper from “The Wonder Years”) but a bonus appearance by the always-great Busy Phillips (“Freaks and Geeks”).

It might not be the cool-kids secret that it once was, but at least “How I Met Your Mother” was able to greet the new Britney-fan viewers in Season Three with the same consistently funny material we’ve all been enjoying for the previous two seasons.

Special Features: Let’s start with the audio commentaries. Unfortunately, the first disc is thoroughly devoid of them, but Disc Two contains a pair (including one with Sarah Chalke) and Disc Three is chock full of commentary, with a half-dozen episodes getting talked over. Every regular cast member is represented at least once, but the funniest is probably Jason Segel, who is ostensibly drunk and trying to forge a homoerotic bond with writer Chris Harris. There’s a fair amount of extra material that had previously only appeared online, including “Lily and Marshall’s Honeymoon Videos,” additional “How It Really Happened Scenes,” and the cast members’ favorite episodes. Also there is a retrospective featurette to sum up the first two seasons (a nice idea for those who only came aboard with Britney’s appearance), along with a start-to-finish look at an episode (“We’re Not From Here”) and an unrated gag reel. The odds of most viewers making it all the way through the audio track of “Ted Mosby Is A Jerk” are slim (the song is 20 minutes long, with the vocalist taking a puke solo – yes, you read that correctly – somewhere around the 8:15 mark), but the vids for Marshall’s “You Just Got Slapped” and Robin Sparkles’ “Sandcastles in the Sand” are genius, particularly the latter’s guest appearances by Alan Thicke, James van der Beek and Tiffany.